1. Field of the Invention
The present invention relates to the field of compounds, cements and asphalt mixtures for building up, paving and repairing roads, and more particularly, the invention refers to an asphalt additive as well as to an asphalt cement and an asphalt mixture containing the additive, where the additive, when added to the cement and mixture, causes the latter to be easily manufactured and applied, as well as more lasting and stable.
2. Description of the Prior Art
Many additive compounds such as cements and asphalt mixtures have been developed for an easy manufacturing, application and durability of the asphalt covering. Asphalt or bituminous compositions comprising styrene-butadiene-propylene polymers, propylene and solvent are some of them.
Some of these compositions are disclosed as having acceptable properties at room temperature, such as those indicated in U.S. Pat. No. 5,840,109 and U.S. Pat. No. 3,312,157.
On the other hand, U.S. Pat. No. 5,911,817 discloses mineral lubricant base oils which can be added to asphalt compositions to improve their properties at a low temperature. U.S. Pat. No. 4,878,950 discloses a material for bituminous compositions to cover roofs, containing a low molecular weight olefinic copolymer or homopolymer.
U.S. Pat. No. 5,961,709 discloses an asphalt composition comprising paraffinic oils. U.S. Pat. No. 5,750,598 discloses the addition of a curing agent with sulphur supply to a bitumen/polymer composition.
U.S. Pat. No. 3,312,157 discloses a product of the type of the present invention with a main difference being that such asphalt mixture is prepared with methylbenzene.
None of the above mentioned publications refers to the ultimate achievement which is an asphalt mixture manufactured in similar conditions to hot manufactured asphalt concrete and applied at temperatures near 90°, quite lower than the conventional ones, namely 130° C. to 150° C., achieved with the additive of the invention.
Finally, and truly exceeding the above mentioned referred compositions and additives quality, the additive of the Argentine Patent Application number P020100585 of one of the inventors of this invention, discloses an additive comprised by lubricants, fluxes and solvents such as kerosene, gas oil, etc. Although this additive has proven to have a behavior exceeding the known one, it has still not overcome other problems such as those generated by the solvent such as gas oil, kerosene, etc., which are necessary in these mixtures. However, solvent can not be directly eliminated, unless the composition could be modified so that is may provide the intended results. However, a composition with no solvent keeping this performance has not still been obtained.
For example, during the manufacturing as well as laying or application of asphalt mixtures obtained with solvent content, the temperature values shall be taken into account, since the evaporation of the solvent remaining in the carpet destroys the cohesive structure of the asphalt cover. Besides, from the ecological as well as safety point of view, costs and so on, solvent has been a component which would be desirable not to be used in these additives, but it has not been still removed from them due to the fact that its application has been always necessary to provide the mixture with essential characteristics for working the mixture.
Therefore, it would be convenient to obtain a composition or additive, such as the cements and mixtures used with it, allowing to work the mixtures at low temperatures, apply them to temperatures below the usual working ones, avoiding the structural impairment of the asphalt cover and preventing the risks of contamination and safety of the solvents and the components used in well known conventional additives.